BEIJING - China's top climate change official, Xie Zhenhua, said on Wednesday that climate talks should stick to the dual-track approach in Durban, South Africa, at the end of this year.

His comment came amid the uncertainties over the fate of the Kyoto Protocol after the first commitment period expires at the end of 2012.

"We hope this year's negotiations can stick to the Bali Roadmap and move ahead on the Kyoto Protocol consensus reached to achieve a comprehensive and balanced outcome in Durban," Xie said at the opening ceremony of the two-day high-level international conference on climate change and green, low-carbon development.

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Su Wei, China's chief climate change talks negotiator, also called on delegates to leave no time gap between the first and second commitment periods of the Kyoto Protocol.

Rich and poor countries still disagree on the future of the second commitment period of the Kyoto Protocol, the only international treaty binding nearly 40 industrialized countries to cut greenhouse gas emissions.

The discrepancy between the two groups grew even wider during the previous round of climate change talks, which ended last week in Bonn, Germany, experts said.

While the developing countries have put a high priority on the continuation of the protocol, some industrialized countries, such as Japan, Russia and Canada, have voiced a clear intention to walk away and build a new framework for agreement.

Martin Khor, executive director of the South Centre think tank, said the next few months will be critical for the future of the Kyoto Protocol.

"Developed countries think they have done and offered enough, but actually have not," Khor said, adding it would be "ugly" for developed countries to walk away from their compulsory responsibilities.

Yang Fuqiang, a senior consultant on climate change and energy at the US-based Natural Resources and Defense Council, said that a regulatory gap is unlikely to be avoided, because even if the countries reach a deal at Durban, it will take time for governments to ratify the agreement.

"There are only 18 months left before the first commitment of the Kyoto Protocol expires at the end of 2012. It will be a huge challenge to bridge the differences in time," said Yang.

Developing countries are already pledging greater cuts in greenhouse gas emissions than developed countries, according to a recent study published by the international Charity organization Oxfam. The report estimates that at least 60 percent of emission cuts by 2020 currently on the table are likely to be made by developing countries.